Although ICF construction is one of the best ways to minimize air penetrations into a home, builders must take other measures to ensure maximum airtightness. "People think that just building a home with ICF walls covers it in terms of energy efficiency, but it doesnt," says Richard Rue, CEO of Energy Wise Systems, Mansfield, Texas.

He gives the following common-sense tips for reducing air infiltration:

• Caulk every place in the building framework where air could possibly enter, such as around window and doorframes, sill plates, and plumbing and electrical penetrations.
• Avoid the use of recessed, or canned, lights. "One of these lights represents 1 square foot of uninsulated attic space, and 20 of these lights represents a door open in the attic all the time," says Rue. When a homeowner insists on recessed lights, Rue recommends using a brand that can be insulated and has airtight rings.
• Use "thermally broken" windows, those with wood or vinyl frames as opposed to aluminum, which conducts heat and cold. In northern states, use low-E glass, which reduces heat loss in the winter and heat gain in the summer.
• Avoid the use of sliding glass doors. Rue says that the gaskets on these doors dont seal properly, so they allow a lot of air infiltration. As an alternative, he recommends installing double atrium doors that swing open only on one side.

     Rue often recommends the use of ICFs, calling them the "Ferrari" of exterior wall systems. "About 80% of all air leakage through a house is through the walls," says Rue, "and ICFs eliminate that leakage." He has worked with various ICF manufacturers to help them maximize the energy efficiency of structures built with their systems.